A wireless communication system is a complex network of systems and elements. Typical systems and elements include (1) a radio link to mobile stations (e.g., a cellular telephone or a subscriber equipment used to access the wireless communication system), which is usually provided by at least one and typically several base stations, (2) communication links between the base stations, (3) a controller, typically one or more base station controllers or centralized base station controllers (BSC/CBSC), to control communication between and to manage the operation and interaction of the base stations, (4) a switching system, typically including a mobile switching center (MSC), to perform call processing within the system, and (5) a link to the land line, i.e., the public switch telephone network (PSTN) or the integrated services digital network (ISDN).
A base station subsystem (BSS) or a radio access network (RAN), which typically includes one or more base station controllers and a plurality of base stations, provides all of the radio-related functions. The base station controller provides all the control functions and physical links between the switching system and the base stations. The base station controller is also a high-capacity switch that provides functions such as handover, cell configuration, and control of radio frequency (RF) power levels in the base stations.
The base station handles the radio interface to the mobile station. The base station includes the radio equipment (transceivers, antennas, amplifiers, etc.) needed to service each communication cell in the system. A group of base stations is controlled by a base station controller. Thus, the base station controller operates in conjunction with the base stations as part of the base station subsystem to provide the mobile station with real-time voice, data, and multimedia services (e.g., a call).
Typically, the mobile station may detect the presence of multiple base stations that are operable to provide communication services to the mobile station. To assist with synchronization between the mobile station and those base stations, beacon signals are transmitted. In a Third Generation Partnership Project (3GPP) system, for example, the beacon signal is known as a primary synchronization code (PSC) that is transmitted once per slot. Each base station transmits the same beacon signal. However, the mobile station may receive different versions of a beacon signal from a single base station because the signal may reach the mobile station via a direct path and/or reflections off of objects such as buildings and mountains (i.e., multi-path signals). Because the 3GPP system may asynchronously distribute base stations, the mobile station may receive beacon signals from one base station that is not aligned in time with the beacon signal from another base station. Typically, the beacon signal from a host base station (i.e., the base station providing service to the cell in which the mobile station is currently located) may be received at the mobile station with more power than the beacon signals from base stations providing services to neighboring cells. That is, the beacon signal from the host base station may dominate a multi-path profile observed by the mobile station. As a result, the mobile station may not be able to report the strength of the neighboring base stations to the network.
One aspect of designing a wireless communication system is to optimize the resources available to the mobile station. In particular, one method of improving the availability of resources within the mobile station is to reduce the loading on the digital signal processor (DSP) and to reduce the number of direct memory access (DMA) transfers during a search for multi-path signals. To do so, the mobile station may need to control the number of multi-path signals reported in a search. Therefore, a need exists for a more effective means to report multi-path signals.